<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>JS体验</title>
</head>
<body>

<script>
    // JS代码 打印5次Hello World
    for (i =0;i<5;i++){
        document.write("Hello world")
        document.write("<br>")
    }
</script>

</body>
</html>